What's the difference between tf.placeholder and tf.Variable?

Question

I\'m a newbie to TensorFlow. I\'m confused about the difference between tf.placeholder and tf.Variable. In my view, tf.placeholder is

Answer 1

For TF V1:

1. Constant is with initial value and it won't change in the computation;

2. Variable is with initial value and it can change in the computation; (so good for parameters)

3. Placeholder is without initial value and it won't change in the computation. (so good for inputs like prediction instances)

For TF V2, same but they try to hide Placeholder (graph mode is not preferred).